Closure cap liner and method of making



April 7, 1970 W, E. RlsCH ETAL 3,505,152

CLOSURE CAP LINER AND METHOD OF MAKING Filed July 15, 1966 United States Patent O 3,505,152 CLOSURE CAP LINER AND METHOD OF MAKING William E. Risch and Daniel D. Acton, Lancaster, Ohio,

assignors to Anchor Hocking Glass Corporation, Lancaster, Ohio, a corporation of Delaware Filed July 15, 1966, Ser. No. 565,622 Int. Cl. B32b 31/18, 31/20 U.S. Cl. 156-514 3 Claims ABSTRACT OF THE DISCLOSURE A method and means for forming a perforated, laminated closure liner. Backing material and innerseal material which has had a number of aperatures formed therein are fed to bonding means which heat seals the backing and perforated innerseal to one another except in a zone at the apertures so as to form the liminated liner.

'I'he present invention relates generally to the art of packaging and more particularly to an improved method and means for sealing with a tamper-proof innerseal.

It is common practice to include a membrane-like innerseal sometimes known as a safety seal in sealing certain containers with closure caps. In this process, a thin relatively impermeable membrane is adhered to the container mouth, as for example, onto the rim of a glass container which may contain powdered coffee or other food products. Such a membrane provides an additional sealing element and more importantly forms what is known as a tamper-proof seal. The tamper-proof characteristic results from the fact that these seals are fastened more tightly to the container rim than they are attached to the adjacent portions of the closure cap such as the cap liner. When the consumer removes the closure cap, the innerseal remains attached to the container mouth giving a clear indication to the consumer that the package seal has not been broken by others. A prior attempt to tamper with or inspect the contents of the package results in the destruction of this innerseal.

While packages thus sealed have met with general acceptance, this type of sealing using an innerseal has been found to result in product loss and consumer disfavor uponoccasions when a blow-out has accompanied the piercing of the innerseal after removal of the metal closure cap. These product blow-outs or explosions occur where gas pressure within the sealed packages has substantially exceeded atmospheric pressure at the point when the containers have been opened. As soon as the customer pieces the innerseal, a rapid discharge of container headspace atmosphere is accompanied by a discharge of some of the packaged product such as powdered milk or coffee or the like. These differences in headspace and atmospheric pressure, may result from the shipment of products to elevated locations which include substantial portions of some of the western states.

Previous attempts to eliminate this product loss have included perforation of the assembled safety seal liner either before or after the insertion of the liner into the cap by moving a perforating means over the membrane side of the membrane cover pulp backing. This practice has not satisfactorily solved the problem as it has been found that perforating in this manner results in a loss of the seal due to the probable perforation of not only 'the membrane but also of the wax or other sealing layer on the pulp backing permitting leakage through the berous backing. In addition, perforations thus formed have not been found to provide the necessary venting action since the wax or other adhesives which temporarily bond the innerseal to the pulp board have been found to enter the perforations during the perforating operation resulting in insufficient venting through the membrance perforations after the caps are removed.

The method and means of the present invention overcome these disadvantages by providing an effective perforated -venting membrane and which eliminates the above described tendency of the perforations to be reclosed by the wax layer on the pulp backing.

An object of the present invention is to provide an improved method and means for sealing using an innerseal or safety seal membrane.

Another object of the present invention is to provide an improved innerseal for use with packages used at elevated locations.

Another object of the present invention is to provide an improved venting type of cap liner including an innerseal.

Another object of the present invention is to provide an improved continuous method of forming venting type cap liners including an innerseal membrane.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described or will be indicated in the appended claims, and various advantages not referred to herein Will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specication wherein:

FIG. 1 is a diagrammatic view illustrating a method and means for forming an improved cap liner in accordance with the present invention;

FIG. 2 is a perspective view of a cap liner including an innerseal formed in accordance with the method of FIG. l;

FIG. 3 is a vertical sectional view taken along line 3-3 on FIG. 2;

FIG. 4 is a vertical sectional view of a cap including a liner in accordance with the present invention;

F'IG. 5 is a vertical sectional view of a container sealed with a cap including a liner in accordance with the present invention;

FIG. 6 is a vertical sectional view corresponding to FIG. 5 showing the cap removed from a container;

FIG. 7 is a perspective view of the container of FIG. 6 with the cap removed with the innerseal still in place; and

FIG. 8 is a vertical sectional view of the bonding iron taken along line 8-8` on FIG. 1.

The composite sealing liner 1 in accordance with the present invention includes a relatively thick pulp backing 2 cut from pulpboard and having a thin low permeability innerseal or membrane 3 detachably adhered to a waxed facing 4 on the pulp backing 2. The innerseal 3 may be formed of two-ply wax laminated glassine paper or possibly plastic or metallic foil or another material which has a high degree of impermeability to gas or air and -whose use is not incompatible with the particular product packaged and which is also easily ruptured or torn by the customer.

FIG. 1 is a diagrammatic illustration of a preferred embodiment of the method of apparatus of the present invention for forming venting liners including such an innerseal. A supply of the pulp backing material 2 is illustrated at a suitable supply point in a roll 5 and being fed towards a bonding iron 6 and punching equipment 7. A supply of the membrane or innerseal material 3 is shown in roll 8 being fed along towards perforating means 9 and bonding iron 6. The web of pulp backing 2 has an air barrier on its upper surface comprising the heat softened wax facing 4.

In the preferred embodiment, the necessary number of venting holes or perforations are formed in the innerseal material 3 by a rotating perforating wheel 11 or other suitable perforating device which most conveniently forms a continuous line of such perforations 10 positioned so that they extend across the assembled liner 1. Other arrangements of the perforations may be used and the size of the perforations is made large enough to provide for the passage of the gases but small enough to keep the particles of the packaged product within the container. At the left-hand side of FIG. 1, the pulp backing material 2 and the innerseal material 3 are shown being laminated together by a heated bonding iron 6 which applies heat and pressure to cause the wax facing 4 to adhere the innerseal material to the backing 2. A light attachment of the innerseal material 3 and the backing material 2 results.

As illustrated in FIGS. 1 and 8, the backing 2 and innerseal 3 are brought together between the heated bonding iron 6 and a platen 15. The bonding iron 6 is so constructed that a series of ribs 16 only contact the innerseal 3. As the innerseal 3 passes under these heated ribs 16 the heat is conducted through the innerseal to the wax facing 4 of the backing material 2 which melts and flows adhering the backing 2 and the innerseal material 3 together. The conguration of the ribs 16 causes the innerseal 3 to have a minor washboard contour with the bond generally limited to the area where the rib 16 of the bonding iron 6 has made contact.

In the area Where the perforations 10 pass under the iron 6, several ribs 16 have been removed. By so designing the bonding iron 6 the heated wax 4 will not flow the distance spanned by the ribs and thus will not seal the perforations 10. Also, the washboard configuration obtained by the iron 6 will cause the innerseal 3 to lift from the backing 2 in this area further assuring that the perforations 10 will not be sealed by the wax 4.

A punch and die means 7 is diagrammatically illustrated at the left-hand of FIG. 1 by which the composite liners 1 with innerseals 3 are punched from the laminated material 12.

FIG. 3 shows a section through a preferred embodiment of the composite liner 1 illustrating in exaggerated form the washboard shape of the innerseal 3 and particularly the lifted portion 14 at the perforations 10.

FIGS. 4-7 illustrate the application and removal of a cap 20 from a container 21 of the typical type used to package products such as powdered coffee or powdered milk or others and which have been subject to the blowouts described when sealed using innerseals of prior form.

FI G. 4 illustrates a liner 1 inserted into a typical lined closure cap 20 prior to the application of the cap 20 to a container.

FIG. 5 illustrates a sealed container 21 with the innerseal 3 engaged with and cemented to the container rim 22 and with a tightly sealed package assured by the backing 2 and its uninterrupted wax coating.

FIG. 6 illustrates the closure cap 20 removed from the container 21 and shows the innerseal 3 still tightly attached to the container rim. The seal 3 has been stripped from its light attachment to the backing 2 as the cap 20 is removed. The line of the clear and open perforations 10 now permits rapid venting of the container headspace gases thereby eliminating any blow-outs.

FIG. 7 illustrates the opened container 21 with the innerseal 3 in place and shows the line of exposed perforations 10 extending across the exposed innerseal 3.

It will be seen that an improved cap liner of the innerseal or tamper-proof type has been described which is useful for providing such a seal in all normal innerseal applications and which is particularly useful for eliminating product blow-outs such as are now experienced where such seals have been used for products transported through or used at elevated locations or with products which contribute to a -build-up of pressure in the container headspace causing the product blow-out as soon as the'- innerseal is pierced by the consumer.

An improved seal is provided giving the desired results and which is relatively easily manufactured by the preferred method described herein and which permits the continuous manufacture of the innerseal type liners on continuously operating machinery relatively easily obtained by modifying that now being used to make the prior types of liners with which the above described difculties have been encountered.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of 'the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. Apparatus for continuously forming a laminated closure cap liner having a perforated innerseal layer and a backing layer lightly bonded thereto with one of the facing surfaces of said layers having a thermoplastic adhesive thereon comprising the combination of a lbonding means, means for feeding a web of backing material to the bonding means, means for feeding a web of innerseal material to the bonding means, perforating means positioned in advance of said bonding means for perforating said innerseal material, said feeding means being positioned so that the adhesive coating on the surface of one web faces a surface of the other web, said bonding means comprising heated rib members, and means to force the moving webs together and against said rib members with the ribs spaced from said perforations in said innerseal material.

2. The apparatus as claimed in claim 1 which further comprises means for punching a liner from the laminated webs.

3. The apparatus as claimed in claim 1 in which said perforating means comprises a perforating wheel with radially oriented perforating members.

References Cited UNITED STATES PATENTS 1,597,677 8/1926 Everett 156-252 2,180,338 11/1939 Cloud 156-201 DOUGLAS l. DRUMMOND, Primary Examiner Us. C1. X.R. 156-581, 583 

